1. Field of the Invention
The present invention relates to a substrate with recess portions for microlenses, a microlens substrate, a transmissive screen, a rear type projector, and a method of manufacturing a substrate with recess portions for microlenses.
2. Description of the Related Art
A display device which projects pictures on a screen is known. As for such display device, a rear type projector applied to a home theater monitor, a big-screen TV, and the like is known.
One known rear type projector includes a lens substrate (microlens substrate) having microlenses. In such a rear type projector, there is an advantage in that the view angle characteristic is improved both in the horizontal direction and in the vertical direction of the screen due to photorefractive effect of the microlenses.
A conventional microlens substrate includes a plurality of microlenses of one size arranged on a substrate. The microlenses have a nearly circular shape or the like and are disposed in a staggered-grid shape or the like (for example, refer to Japanese Unexamined Patent Publication No. H. 5-509416 (FIG. 1)). In such a microlens substrate, a flat portion, where the condensing effect by the microlenses is not obtained, is formed in the relatively large region between the microlenses. This flat portion cannot condense the light irradiated to the microlens substrate, and allows the light to be transmitted as straight-traveling light. As a result, in the rear type projector using such a microlens substrate, a sufficient view angle characteristic is not obtained.
The present invention is intended to provide a substrate with recess portions for microlenses which allows manufacturing a microlens substrate having an excellent view angle characteristic, and to provide the microlens substrate having an excellent view angle characteristic, a transmissive screen, and a rear type projector, and further to provide a method of manufacturing the substrate with the recess portions for the microlenses which allows manufacturing the microlens substrate having an excellent view angle characteristic.